Malte UblandClaude Opus 5.5 177b2fde49 Cross package values at their declared type where the JS literal type lacks members
An opted-in package's JavaScript types its own values. The lowering types
a consumer's view of such a value from that JavaScript, and the
declaration boundary (decl-projection.ts) casts to the declared type only
where the JavaScript world answers `any`. A function that returns an
object literal has a precise JavaScript type, so it never crossed, even
where that literal type lacks members the declarations promise:

- `{ [key: string]: string }` over `{ size: "12px" }`: the consumer read
  `settings["font"] ?? "x"` through the literal's fixed key set. The
  checker types the miss `any` (a JavaScript literal), but the keyed read
  took the declared fields' common type, so the miss trapped with
  "record has no key" and aborted the process.
- an expando `out.max = ...` on a non-empty literal, which the JavaScript
  checker leaves out of the literal's type: reading `stats(xs).max` was
  refused with SC1090.

A package value whose JavaScript type is an object literal that lacks a
declared property or string index signature now crosses at its declared
type, so missing keys read undefined through the index signature and
expando members are read from the object. An index signature whose values
do not project (a package interface) keeps the value untyped (`as any`),
so its reads are the JavaScript reads. Only programs compiled with
--npm-static whose consumers read such values are rewritten.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-25 11:51:24 -07:00
2026-10-16 10:33:14 -05:00
2026-10-24 01:57:53 -05:00
2026-10-14 17:27:02 -05:00
2026-10-23 20:51:00 -05:00
2026-07-22 18:08:04 -05:00
2026-10-22 04:10:59 -05:00
2026-10-23 10:14:37 -05:00
2026-10-23 10:14:37 -05:00
2026-07-22 18:08:04 -05:00

scriptc

Vercel Labs Experiment npm version: scriptc License: Apache-2.0 npm downloads per month: scriptc

scriptc compiles TypeScript and JavaScript to native executables and WebAssembly. It uses the types checked by the TypeScript compiler to generate machine code, and the output runs without Node.js installed. npm packages your program imports compile along with it. Code scriptc can't compile is reported at build time with a diagnostic and, where available, a rewrite hint.

scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. Run scriptc coverage on an existing program to see how much of it compiles, and see the limitations and Node.js compatibility reference for details.

Installation

Install with Node.js 24 or later and npm:

$ npm install -g scriptc

The installed compiler runs natively on macOS, Linux, and Windows. Node.js is needed only to install it and to run WASI modules with scriptc run. Standalone compiler archives are also available from GitHub Releases.

Building executables requires a linker and the platform SDK or sysroot. See the quickstart for prerequisites and platform support for host requirements, cross-compilation, and WebAssembly.

Build a program

Create hello.ts:

const who = process.argv.length > 2 ? process.argv[2] : "world";
console.log(`hello, ${who}`);

scriptc run compiles the file and runs the result:

$ scriptc run hello.ts
hello, world

scriptc build writes an executable:

$ scriptc build hello.ts -o hello >/dev/null
$ ./hello scriptc
hello, scriptc

These examples use POSIX shell syntax. On Windows, build hello.exe and run it with .\hello.exe.

Use scriptc coverage hello.ts to check what compiles before you build. See coverage reports for details.

Use Node APIs

Supported Node APIs compile to the native runtime. For example, server.ts:

import { createServer } from "node:http";

const server = createServer((req, res) => {
  res.setHeader("content-type", "application/json");
  res.end(JSON.stringify({ path: req.url }));
});

server.listen(8080, () => {
  console.log("listening on http://localhost:8080");
});
$ scriptc build server.ts -o server >/dev/null
$ ./server
listening on http://localhost:8080

Use npm packages

npm packages compile into the executable with your code, so it doesn't read node_modules at runtime.

Create cli.ts:

import pc from "picocolors";

console.log(pc.green("hello from scriptc"));
$ npm install picocolors
$ scriptc build cli.ts -o cli >/dev/null
$ ./cli
hello from scriptc

Package support is partial. See npm dependencies for which packages compile and how to check them.

Documentation

Contributing

See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.

S
Description
GitHub Trending: vercel-labs/scriptc
Readme Apache-2.0
232 MiB
Languages
TypeScript 68%
C 23.2%
JavaScript 8%
C++ 0.7%